1. Technical Field
The present invention is directed toward casement hinges for windows, and more particularly toward improved track pivots of casement hinges.
2. Background Art
The casement window has a window sash movably mounted within a frame by a pair of hinges mounted between the window frame and the top and bottom of the window sash. It is typical of such a hinge to have a track mountable to the window frame and a sash arm connectable to the window sash. A support arm interconnects the track and the sash arm, with the support arm being pivotally connected to the sash arm and to the track. The sash arm is pivotally connected to a mounting shoe which is supported and guided for movement lengthwise of the track. Window hinges of this type are shown, for example, in Tacheny et al. U.S. Pat. No. 4,726,092 and Sandberg et al. U.S. Pat. No. Re. 32,846 (the latter of which shows a snap stud for defining the pivot which is fixed relative to the track).
A variation on the above described hinge includes an intervening link between the sash arm and the movable shoe to provide for an offset sash arm. Such hinges typically include a second intervening link between the support arm and the movable shoe to provide further support. A window hinge of this type is shown, for example, in Vetter U.S. Pat. No. 4,674,149.
When window hinges of the above type are installed, proper operation and sealing of the window when closed requires that the fixed track pivot (usually between the support arm and the window frame) be properly located relative to the window sash. Further, over the life of the window, the proper location of the fixed track pivot may change due to slight shifting of the window, window frame, etc., resulting in a sag in the sash. Sash sag is a condition formed when the sash and the frame of a window are no longer square to one another (in the closed position), or the edge of the sash which is opposite the hinges seems to sag in comparison to the frame of the window. As a result, the window may not seal tightly or open and close easily.
Heretofore, precise installation of the hinge and later correction of sash sag has usually required that the hinge track be provided with slotted holes and that the hinge mounting screws in the slotted holes be removed to allow for shifting of the track. Repeated removal of such screws can, however, over the life of a window result in a gradual loosening of the strength of the mounting. Further, setting of the frame to properly position the window sash can necessitate that the window be first opened (to allow access to the hinge for adjustment) and then closed (to check the sash alignment). If the adjuster chooses to securely tighten the screws before checking the alignment, subsequent adjustments require that the screws be loosened again, which further exacerbates the potential loss of strength in the mounting. If, instead, the adjuster chooses to check the alignment before securely tightening the screws, then the track can slip when the window is reopened to allow access to the screws for tightening, with the result being that the track once finally tightened might still be slightly misaligned.
The present invention is intended to avoid one or more of the problems discussed above.